Gas and liquid fuel burner combination



Nov. 16, 1965 R. D. REED ETAL 3,217,779

GAS AND LIQUID FUEL BURNER COMBINATION Filed July 18, 1963 INVENTORS ROBE/P7" 0. REED HER$HEL GOODNMWT' ATTORNEY United 3,217,779 GAS AND LIQUID FUEL BURNER COMBINATION Robert 1). Reed. and Hershel Goodnight, Tulsa, 01th.,

assignors to John Zink Company, Tulsa, Okla, a corporation of Delaware Filed July 18, 1963, Ser. No. 295,989 3 Claims. (Cl. 15811) The present invention relates to apparatus for burning either gaseous or atomized liquid or both of such fuels and the invention pertains to improvements of such fuel burning equipment to provide for combustion of the fuel Within a relatively small area closely adjacent the downstream end of the burner assembly and to provide structure which insures stable operation throughout a wide range of heat release and provide apparatus which serves to burn heavy fuels having low ratio weight percentages of hydrogen to carbon.

It is an object of the invention to provide improvements in apparatus for the combustion of liquid and gaseous fuels and to provide ceramic structure in association with the fuel burner heads to retain more heat in the presence of the burner tips for the gaseous fuel and to direct the air generally transversely of the burning liquid fuel to promote penetration of the air deep into the mass of the burning fuel and thereby accelerate the rate at which the fuel burns to complete combustion within a small cubical volume immediately downstream of the burner assembly.

A further object of the invention is to provide a ceramic member in association with the burners so shaped and disposed as to prevent heat from rapidly escaping from the presence of the burner heads for the gaseous fuel thereby providing higher temperatures in the vicinity of the gaseous fuel burners to promote stable operation throughout a wide range of flow of both types of fuels where the burner assembly functions safely and stably over a large range of heat release.

A still further object of the invention is to provide a surface on the ceramic structure associated with the burner which serves to intercept movement of air and to cause it to flow generally in the direction of a movement of the gaseous fuel to accelerate the rate of burning and thereby provide apparatus for the combustion of heavy fuels delivered at relatively low pressures.

Other objects and features of the invention will be appreciated and become apparent to those skilled in the art to which the invention pertains as the present disclosure proceeds and upon consideration of the accompanying drawing taken in conjunction with the following detailed description wherein an embodiment of the invention is disclosed.

In the drawing:

FIG. 1 is an axial sectional view of a burner assembly exhibiting the invention and taken on the line 1--1 of FIG. 2.

FIG. 2 is a plan view on a smaller scale.

FIG. 3 is an enlarged fragmentary sectional view taken on the line 3-3 of FIG. 1 with one of the burner heads for the gaseous fuel shown in plan.

FIG. 4 is a sectional view taken on the line 44 of FIG. 3.

FIG. 5 is a fragmentary section taken on the line 55 of FIG. 3.

The invention is directed to apparatus for the combustion of fuel and is designed to be mounted in the floor of a furnace to be fired. The wall 10 is provided with an opening 11 for accommodating a ceramic member 12 which substantially fills the opening in the furnace wall. The outer face of the wall 10 may be covered with sheet material 16 which also overlies the outer end of the ceramic member 12.

Patented Nov. 16, 1965 The ceramic member 12 is provided with a frustoconical surface 17 which flares outwardly in proceeding downstream of the assembly and thus diverges from the axis 18 of the assembly. A distinct annular recess 19 is provided within the body of the ceramic member 12 which forms an important feature of the structure. An annular flange 21 on the ceramic member 12 provides a continuous ledge having a downstream face 22 which defines the bottom wall of the annular recess 19. The face 22 preferably lies in a plane substantially at right angles to the axis 18 of the burner assembly and which also represents the axis of the ceramic member 12. A continuous frusto-conical upstreamfacing surface 23 forms the top wall of the recess 19. The surface 23 is continuous and lies in a plane which is generally normal to the axis 18 and joins the frusto-conical surface 17 at an acute angle to provide a sharp corner 24 which extends around the interior of the ceramic member 12. The corner edge 24 or the juncture between the frusto-conical surface 17 and the frusto-conical surface 23 is made as sharp as possible with the available ceramic materials. This sharp annular lip and the recess 19 provide important structural characteristics and the functions thereof will be appreciated as the present disclosure proceeds.

Elements for supporting the fuel burner head in operative association with the ceramic member 12 and for supplying controlled quantities of air to the combustion zone are carried by a ring 26 which may be anchored to the wall 10. An annular member 27 is supported in spaced relationship from the ring 26 by means of a plurality of circumferentially spaced bolts 28. An air register stator 29 and an air register rotor 31 are provided between the ring member 26 and the annular member 27. The air register rotor 31 may be rotated by means of a handle 33 to control the volume of air admitted into the assembly for movement into the combustion zone.

A second ceramic member 36 encased in a metal sheath 34 is mounted within the air register and supported by the annular member 27. The downstream end portion of the ceramic member 36 extends into the open upstream end of the ceramic member 12. The ceramic member 36 is of such diameter as to provide an annular passage 35 between the exterior of the ceramic member 36 and the inner edge surface of the flange 21. The ceramic member 36 is provided with an inner frusto-conical surface 37 which flares outwardly from the axis 18 in proceeding downstream of the assembly. The frustoconical surface 37 may be parallel to the frusto-conical surface 17 but a more important structural relationship is that the frusto-conical surfaces 37 and 17 provide a progressively larger cross sectional area around the axis 18 in proceeding downstream of the burner assembly. The refractory member 36 has a passage therethrough and the smallest diameter is indicated at the plane D. The annular surface forming the passage within the ceramic member 36 upstream of the plane D is desirably of arcuate shape to promote entry of air for movement furnaceward through the ceramic member 36.

A liquid fuel burner nozzle may be supported in operative relationship with other elements of the assembly by means of a yoke 41 having a collar 42 through which a guide tube 43 for the conduit supplying liquid fuel to a nozzle 44 extends. A disc 46 is mounted for sliding movement on the guide tube 43 and serves to control the volume of air admitted through an opening 47 in the annular member 27 for movement through the central open area of the ceramic member 36. The nozzle 44 for discharging atomized liquid fuel is mounted in a position upstream of the plane D or that portion of the opening in the ceramic member 36 which has the smallest diameter. The nozzle 44 is thereby located upstream of the zone of the greatest velocity of air moving furnaceward through the ceramic member 36 and created by the pressure drop across the narrow neck of the opening.

An annular manifold 51 is supported by the member 27 into which a gaseous fuel mixture is supplied under pressure through a conduit fitting 52. A plurality of pipes 53 are connected to and are in open communication with the manifold 51 and extend therefrom. The pipes 53 are desirably equally spaced circumferentially of the burner assembly and each pipe carries a burner tip 56 for the gaseous fuel. Each burner tip as is connected to the upper end of its supply pipe 53. Each burner tip is desirably provided with fiat faces one of which is adapted to lie along the inner circumference 57 of the annular flange 21 as best shown in FIG. 3. The downstream end portion of each nozzle 56 is frusto-conical shape and a discharge port 61 is provided in each burner tip 56. The axis of the discharge port 61 is at an acute angle A with respect to a radial plane 60 of the burner assembly as shown in FIG. 3 and which may be about thirty degrees. The discharge port 61 in each gaseous fuel burner tip 56 provides for the discharge of a portion of the gaseous fuel generally radially outward and towards the annular surface 63 defining the perimeter of the recess 19. The discharge of the gaseous fuel from each port 61 is also downstream of the surface 22 as will be appreciated from a consideration of FIG. 5.

Each burner tip 56 for the gaseous fuel is provided with two additional discharge ports 66 and 67. The axis of the discharge port 66 is in alignment with the radial plane 60 and the axis of the discharge port 67 diverges at an acute angle F from the axis of the port 66 in proceeding radially inwardly of the assembly. The axes of the discharge ports 66 and 67 are inclined and provide for the discharge of the gaseous fuel in directions which converge towards the axis 18 of the burner assembly.

In operation and when the liquid fuel is ignited by any suitable type of pilot (not shown) a generally conical flame is developed with diagrammatically is depicted in FIG. 1. In proceeding downstream from the smallest diameter D of the passage through the ceramic member 36 there is a continuous and progressive increase in the area downstream of the burner nozzle which accommodates rapid expansion of the burning fuel. Air flows through the yoke 41 and through the opening 47 to the narrowest portion D of the internal passage in the ceramic member 36. The velocity is the greatest in the vicinity of the plane D because of the pressure drop throughout,

this narrow neck. The nozzle 44 for the liquid fuel is located upstream with respect to the greatest air velocity and such disposition of the nozzle 44 represents an important feature of the assembly and contributes to the result of burning heavy fuels having a low ratio weight percentage of hydrogen to carbon.

The air entering through the openings in the air register elements 29 and 31 moves furnaceward exteriorly of the ceramic member 36 and through the annular passage 35. This air impacts against the frusto-conical surface 23. The frusto-conical surface 23 directs the air radially inwardly and in directions which are substantially at right angles to the movement of the burning fuel. The air moves substantially in the direction of the arrows 55. The angle at which the air enters the burning fuel assist in the rapid burning because the direction of movement of the air drives oxygen deep into the mass of burning fuel.

The heat developed by the burning of gaseous fuel escaping through the tips 56 does not move freely towards the furnace chamber but is intercepted by the surface 23 and held in close proximity to the gaseous fuel which escapes through the discharge ports 66 and 67. Heat is thus retained in the annular recess 19 and such characteristics contribute to extremely stable operation which is maintained throughout a wide range of the voltime of fuel discharged from the burner tips 56. The improvements in the stable operation resulting from the development of a higher temperature level within the recess 19 accelerates burning of the fuel. The surface 23 directs the air flow to closely follow the flow of the gaseous fuel for further acceleration or burning by presenting more oxygen in the presence of the burning fuel to provide a burner assembly which provides for combustion of heavy fuels having low ratio weight percentages of hydrogen to carbon at readily attainable pressures. The surface 23 provides for guiding air generally radially inwardly into the mass of burning fuel to further promote rapid burning.

While the invention has been described with reference to particular organization of elements and with regard to the particular shape of the ceramic members and in relation to particular types of fuel burner heads it will be appreciated that changes may be made in the overall assembly as well as in the various elements. Such modifications and others may be made without departing from the spirit and scope of the invention as set forth in the appended claims. 1

What we claim and desire to secure by Letters Patent is:

1. In a fuel burner assembly, a first ceramic member having a first frusto-conical inner surface diverging in proceeding downstream of the burner assembly, said ceramic member having an annular recess therein at the upstream end of said frusto-conical surface, an annular face on said ceramic member defining the upstream wall of said recess, a plurality of circumferentially spaced burner tips within said ceramic member adjacent said recess, means for supplying gaseous fuel to said burner tips, each of said burner tips having a discharge port disposed to direct gaseous fuel into said recess downstream of said annular face and said port having its axis disposed at an acute angle with respect to a radial plane of the burner assembly which intercepts the longitudinal axis of the associated burner tip, a second frusto-conical surface on said ceramic member forming the downstream wall of said recess and joining the first frusto-conical surface at an acute angle and providing an annular lip sharp in section radially inwardly of said burner tips, a second ceramic member projecting into the first ceramic member providing an annular passage between the exterior of the second ceramic member and the first ceramic member, said second ceramic member having a passage therethrough with one portion of smaller diameter than other portions of said passage, a nozzle for liquid fuel supported within said passage upstream of said small diameter portion, a third frusto-conical surface within the second ceramic member flaring from the axis of the burner assembly in proceeding downstream from said small diameter portion of said passage, and means admitting air for movement through said annular passage into impact engagement with the second frusto-conical wall where it is diverted radially inwardly substantially at right angles to the axis of the burner assembly.

2. In a fuel burner assembly according to claim 1 wherein the second frusto-conical surface is disposed generally normal to the axis of the burner assembly.

3. In a fuel burner assembly according to claim 1 wherein the third frusto-conical surface is in substantial alignment with the first frusto-conical surface.

References Cited by the Examiner UNITED STATES PATENTS 1,801,431 4/1931 Irish 158-11 1,986,796 1/1935 De Florez 15899 2,847,063 8/1958 Reed et al 15811 3,033,273 5/1962 Zink et a1 158- JAMES W. WESTHAVER, Primary Examiner.

MEYER PERLIN, Examiner. 

1. IN A FUEL BURNER ASSEMBLY, A FIRST CERAMIC MEMBER HAVING A FIRST FRUSTO-CONICAL INNER SURFACE DIVERGING IN PROCEEDING DOWNSTREAM OF THE BURNER ASSEMBLY, SAID CERAMIC MEMBER HAVING AN ANNULAR RECESS THEREIN AT THE UPSTREAM END OF SAID FRUSTO-CONICAL SURFACE, AN ANNULAR FACE ON SAID CERAMIC MEMBER DEFINING THE UPSTREAM WALL OF SAID RECESS, A PLURALITY OF CIRCUMFERENTIALLY SPACED BURNER TIPS WITHIN SAID CERAMIC MEMBER ADJACENT SAID RECESS, MEANS FOR SUPPLYING GASEOUS FUEL TO SAID BURNER TIPS, EACH OF SAID BURNER TIPS HAVING A DISCHARGE PORT DISPOSED TO DIRECT GASEOUS FUEL INTO SAID RECESS DOWNSTREAM OF SAID ANNULAR FACE AND SAID PORT HAVING ITS AXIS DISPOSED AT AN ACUTE ANGLE WITH RESPECT TO A RADIAL PLANE OF THE BURNER ASSEMBLY WHICH INTERCEPTS THE LONGITUDINAL AXIS OF THE ASSOCIATED BURNER TIP, A SECOND FRUSTO-CONICAL SURFACE ON SAID CERAMIC MEMBER FORMING THE DOWNSTREAM WALL OF SAID RECESS AND JOINING THE FIRST FRUSTO-CONICAL SURFACE AT AN ACUTE ANGLE AND PROVIDING AN ANNULAR LIP SHARP IN SECTION RADIALLY INWARDLY OF SAID BURNER TIPS, A SECOND CERAMIC MEMBER PROJECTING INTO THE FIRST CERAMIC MEMBER PROVIDING AN ANNULAR PASSAGE BETWEEN THE EXTERIOR OF THE SECOND CERAMIC MEMBER AND THE FIRST CERAMIC MEMBER, SAID SECOND CERAMIC MEMBER HAVING A PASSAGE THERETHROUGH WITH ONE PORTION OF SMALLER DIAMETER THAN OTHER PORTIONS OF SAID PASSAGE, A NOZLE FOR LIQUID FUEL SUPPORTED WITHIN SAID PASSAGE UPSTREAM OF SAID SMALL DIAMETER PORTION, A THIRD FRUSTO-CONICAL SURFACE WITHIN THE SECOND CERAMIC MEMBER FLARING FROM THE AXIS OF THE BURNER ASSEMBLY IN PROCEEDING DOWNSTREAM FROM SAID SMALL DIAMETER PORTION OF SAID PASSAGE, AND MEANS ADMITTING AIR FOR MOVEMENT THROUGH SAID ANNULAR PASSAGE INTO IMPACT ENGAGEMENT WITH THE SECOND FRUSTO-CONICAL WALL WHERE IT IS DIVERTED RADIALLY INWARDLY SUBSTANTIALLY AT RIGHT ANGLES TO THE AXIS OF THE BURNER ASSEMBLY. 